Press for molding plastic substances



w-. H. sMl-rH 4 Filed June e, 192s s sheewsheet 1 PRSS FOR HOLDINGPLASTIC SUBSTANCBS June 16, 1925.

June 16, 1925. 1,542,739

' w. H. SMITH PRESS FOR HOLDING PLASTICxSUBSTANCES Filed June 6, 1923 3Sheets-Sheef 2 pag.2.

June 16, 1925.

W.- H. SMITH PRESS FOR MOLDING PLASTIC SUBSTANCES 3 Sheets-Sheet 3 FiledJune 6, 1925 Patented June 16, 1925,

UNITEDv STATES PATENT OFFICE.

WILLIAM HERBERT SMITH, OF EAST MOLESEY, ENGLAND, ASSIGNOR T0 TRIANGULARCONSTRUCTION COMPANY LIMITED, 0F EAST MOLESEY, ENGLAND.

IRESS FOR MOL'DING PLASTIC SUBSTANCES. v

Application filed June 6,

To @ZZ whom it may concern:

Be it known that I, VVILLTAM HERBERT SMITH, a British subject, residingat The Bungalow, Imber Court, East Molesey, in the county of Surrey,England, have invented, certain new and useful'lmprovements in Pressesfor Molding PlasticV Substances, of which the following is aspecilicatiom This invention relates to presses for' molding plasticsubstances and is particularly applicable to presses for forming blocksor slabs of concrete and like substances'.

Ank object of the invention is to provide an improved press having adouble toggle operating mechanism.

A further obj ect is to provide such a press wherein one toggleJfunctions in applying the necessary pressure to the material in the moldand will hereinafter be referred to as the pressure toggle and the othertoggle functions in stripping or ejecting the molded article from themold and will'hereinafter be referred to as the ejection toggle,

' the movable links of both toggles. being connectedat different pointsto a common transmission member in operative connection with a plunger.

In the preferred form of the press the movable plunger is connected to alink, which will be termed the transmission lever which is pivotallyconnected at its far end to the movable link of the pressure toggle andat anintermediate point to'themovable link of thek ejection toggle.' f

The press will be described in a form suitable for hand operation but itis to be understood that power operated lmeans may be substituted forthe hand levers described.

Although the invention is applicable to machines in which positiverelative movement between pressure platev and mold is given at one endonly, it is preferred to embody vit in a machine in which such relativemovement is given at both ends of the mold.

Other objects and features of the invention will be understood from thefollowing Y description of a preferred form of 'press and from theappended drawings, wherein Figr. 'l represents a side elevation of themachine, partly 1n sectiomthe various levers 1923. serial No; 643,739.

beingshown in their positions during filling of the mold.

Fig. 2 represents a front elevation of the machine partly in section.

Fig. 3 yis a diagrammatic view showing the various levers in theirposition at which the material in the mold is subjected to maximumcompression.

Fig. 4 is a similar diagrammatic view at the end of the ejectionmovement.

The press is provided with a mold' A provided with a movable bottomplate B; this bottom plate is supported by a number of pressurey rods Ccarried bv a cross-head I) which is guided in the hollow standards Earranged at the sides of the machine. Two operating hand-levers areprovided; one, the pressure lever F applies the pressure to the mold,and the other, the ejection lever Gr is employed for ejecting the moldedblock.

Each :of these hand levers is connected through atoggle linkage to atransmission lever Il, and to ensure smoothness of action it ispreferred to provide this linkage and transmission lever mechanism onboth sides of the machine. Y

, The pressure lever F is pivoted on a shaft j and an extension F1thereof is connected by. a link J with pressure Goggles K one of whichis carried by a fixed pivot K1 and the other of which is pivoted totheend of the transmission lever H.

The ejection lever G is pivoted upon a shaft L which carries an arm Mpivoted to n pivot P and the lower of which is pivoted v to the lever Hby a pivot 7L.

A to pressure plate Q is carried by parallel mot on links R normallyheld in raised position by a spring S. The lower link R, carries ashackle provided with a bail T under which engages a hooked top`pressure rod U.

`The operation of the parts so far dee scribed may be summarized asfollows Referring to Fig. l the mold is first filled with concrete orother material to be molded which is conveniently stored in a hopper Z.The top plate Q is then lowered and 1n so doing the hooked rod U snapsover the bail T under the action of a spring a. The ejection togglebeing closed, the pivot /i acts as the ulcrum of the transmission leverH and as the pressure lever f is lowered pressureis applied through thetoggles K to the pivot at the end of the transmission lever thus causingthe cross-head D to rise and the bottom plate B positively to compressthe material in the mold from the bottom thereof. The force applied atthe topof the lever F is magnied three times; once by the lever itselt',then'Y by thel toggle Kand finally by the lever H, the pressureincreasing as.thema-terial in the mold becomes more compacted.

Ars thetransmission lever .lvl moves downwards it exerts a heavy pulltol be `exerted on the rod` U which thus causes a heavy pressuretozbeapplied to the top pressure pla-te Q' which therefore exerts apositive compression et the material in the top of the mold. Thispositive relative movement between Vthe pressure plates and the mold atboth ends thereof ensures homogeneity in the resulting block.

Figz' represents theposition ofthe levers at the point at which thetoggles K, reach dead cen-tre andniaxiniium pressure is CX- verted onlthe mold.4 Further depression of the lever F cause-s the toggles K topass their cleadcentre andthus releases the pressure 'onl the mold thusremoving the grip of the hooked rodU upon the bail T. In

Amed-i-ately after this release of pressure a cam Y on the shaft engagesa roller upon a bell-crank lever lV connected by a rod Vengagingithe rodU, thus causing the latte-r to be pulled1 back-Wards clear of the bailT, whereupon the pressure plate Q rises `angler the action oi'the springS.

The ejecting-lever G is nowf raised and in so doing it breaks the toggleO, and. the

pressure toggle remaining fixed in position just beyond dead centreshown in Fig'. Ll, the pivot 7L noiv Vfunction-sk asl the fulcrum ot thetransmission lever H.. rlhe lever H thus moves further upcarrying withit the bottom plate B and ejreeting the molded block from the mold. VThearrangement-ot the levers isV such that the maximmn ejecting pressure isexertedA on the bottom plate BA at the begin-ning of the ejectionoperation .Whenthe resistance to ejection has its.

maximum value.

Thein-achine is shown Witlrthe moldv designed for the manufaeture ofhollow. blocks of triangular cross-section, Ylor the iormation oftheapertures whereof cores c are employedandbraced front members f, Fig. 2,provide the Walls for the two shorter sides of the triangle.

tion, hollow or solid, may beiormed Within the width capacity of themachine, the

thickness of the blocks being varied by ad,

standards are closed at the topiby covers .fl fi' and the guides aretherefore protected Yfrom concrete or like gritty n'iat'erial falling onto them duringv use of the machine. The trouble commonly experiencedwith bloeit machines due to'elogging oiL the guide sur- 'lfaees istherefore n-iinimixed.

I claim:

l. Tn a block molding press the combinationot amold` adapted to containthe4 material to be moldedatogglc mechanism adapted toapply pressure toLthe material, a second toggle mechanism adapted to eject the compressedmaterial trom the mold. and a transmission member connected at dilierentpoints to both saidI toggle mechanisms and ulcrumed about the .point atAwhich it is connected to the first While vthe second is operativi-3.

Q, In a bloeit molding pressH the combinaotamold adapted to. contain thematerial to be molded a toggle mechanism adapted to apply pressure tolthe material, a second toggle-mechanism adapted to eject the compressedmaterial romthe mold, and a transmission member connected at dill'erentpoints to both said toggle mechanisms and lulcrumed about the point atwhich itI is connected to the second while the first is operative.

3. In a block molding. press thecombination otv amold adaptedtocontainthe material to be molded a, toggle mechanism adapted to apply pressure'to the material, a second togglemechanism adapted-to eject thecompressedimaterial iromthe mold, and a vtransmission member connectedatdilierent points to both .said toggle mechanisms and fulerumed, Whileeither toggle is operative, about` the point. at which it is connectedto the other.

t. In a block. moldingpress, the comliination of a mold adapted tocontain the material to be molded, a toggle mechanism adapted toapplypressure tothe material, a second toggle mechanism adapted toreject thecompressedniaterial from themold, a transmission member connected atdifferent Vpoints. to both said toggle mechanisms and operative, apressure plate at each end of themold and interconnecting mechanismcausing the pressure plates to move in opposite directions relatively tothe mold by the operation of the transmission lever.

5. In a block molding press, the combination of a mold adapted tocontain the material to he molded, a toggle mechanism adapted to applypressure to the material, a second toggle mechanism adapted to eject thecompressed material vfrom the mold, a transmission lever through whichthe movement of the toggle levers is transmitted to a pressure plate atone end of the mold, a hooked tension rod adapted to transmit motion tothe pressure plate at the other end of the mold, and means fordisengaging said tension rod from the pressure plateal'ter the tensionin the rod has been removed.

6. A press for molding blocks of ccncretel or other plastic materials,comprising a pressure plate operatively connected to a transmissionlever, a pressure operating lever, toggle mechanism connecting saidpressure operating lever With said transmission lever,

an ejection operating lever, a second toggle mechanism connecting saidejection operating lever with said transmission lever, and means foraltering the :Fulcrum of said transmission lever according to whether apressure movement or an ejection movement is required substantially asdescribed.

7. A block molding press having a mold, a pair of pressure plates, across-head carrying one of said pressure plates, guiding means for saidcross-head comprising hollou1 standards and means to cover the tops ofsaid standards. c

8. A press for molding blocks of concrete or other plastic materialscomprising a pressure plate operatively connected to a transmissionlever, a pressure operating lever, toggle mechanism connecting saidpressure operating lever With said transmission lever, an ejectionoperating lever, a second toggle mechanism connecting said ejectionoperating lever with said transmission lever and means for altering thefulcrum of said transmission lever according to Whether a pressuremovement or an ejection movement is required substantially as described.

In testimony whereof I aiiix my signature.

. WILLIAM HERBERT SMITH.

